This invention relates to protective sleeves for underground utilities, and particularly to modular protective sleeves which can be put into place by being hauled or dragged through a utility duct which runs between two adjacent manholes, so as to be positioned within the duct and to protect the utility which the modular protective sleeve surrounds while the casing in which the duct is placed is broken.
Most countries in the world, developed and developing, western and eastern, including third world countries, may have many underground utilities that have been put into place or will be put into place in the near future. This is especially true in urban areas of nearly every country, and in many suburban areas particularly of European, North American, Southeast Asian, Australasian, some South American, and some Asian subcontinent cities. Such underground utilities include electrical power distribution utilities, telephone and cable television distribution utilities, other high speed data distribution utilities including particularly optical fibre transmission and distribution systems, and gas distribution systems. All of those utilities are typically buried underground in urban and many suburban areas for reasons of safety, convenience, so as to avoid tampering, so as to avoid urban visual blight, and so on.
Typically, such underground utilities are referred to as buried utilities, and typically they are installed in plastic ducts which are, themselves, surrounded and protected by a concrete casing or barrier. Such ducts are buried at depths from several centimeters up to several meters below the surface, and they range in diameter from, say, 10 cm up to 40 cm or more.
Also, buried utilities that are run in ducts are typically found in ducts which extend in straight lines between adjacent manholes. This provides an opportunity to xe2x80x9cfishxe2x80x9d a line or fishtape, or the like, from one manhole to the next adjacent manhole, a feature which the present invention takes advantage of.
It will also be noted that, in most instances, there is some clearance around any utility cables, wiring, or piping, that is carried through a ductxe2x80x94in other words, the duct is not packed fullxe2x80x94and that is also a feature of which the present invention takes advantage, as will be described hereafter.
However, any buried utility of the sort described above is liable at some time or another to have a fault, whereby wires may short together or insulation may break down, a pipe may collapse, and so on; and in any such instance, it is necessary to dig into the ground at the point where the fault has occurred so as to correct it.
Moreover, it very often occurs that a repair such as a splice or a branch must be installed in or taken from the underground utility, at a particular location. This again requires digging into the ground so as to reach the buried utility at the desired spot.
However, as it has been noted, most such underground utilities are encased in a concrete protective casing which requires to be broken such as by jackhammers or sledge hammers. Typically, jackhammers are used for that purpose.
Obviously, however, the use of a jackhammer in the immediate region of a utility duct creates considerable danger to the utility duct because it is possible that, as the last few centimeters of concrete are broken through by the jackhammer, the point of the jackhammer might pierce into the utility duct. It will be borne in mind that the utility duct is, itself, typically made of plastic such as PVC or the like, having relative hardness and stiffness, but not nearly enough to withstand the slightest impact of a jackhammer.
The purpose of the present invention is to provide a modular protective sleeve which can be positioned inside the underground utility duct at the point where the concrete casing surrounding the duct is to be broken. Then, as the last few centimeters of concrete are broken away and the point of the jackhammer approaches the duct, even if it pierces the plastic material of the duct it will simply glance or bounce or slide off the hard metallic protective sleeve which has been put into position in the place where the jackhammer work is to be done. This protects the utility, so that it may continue to work in an operative manner delivering whatever commodity it is that is within the utility duct.
Thus, a very particular need arises for a modular protective sleeve which can be put into position at a place where the concrete casing which surrounds a buried utility duct is to be broken so as to gain access to the utility within that duct, without disturbing the delivery of the utility commodity.
Typically, a modular protective sleeve in keeping with the present invention may have a length of 30 cm or 40 cm and up to several meters, depending on the nature of the digging and concrete breaking activity that is to be undertaken. The purposes for varying lengths of modular protective sleeve are manifold, including the fact that if a fault has occurred it may not be possible to precisely locate its position within, say, a few centimeters. Moreover, it may sometimes occur that a length of duct of several meters or more may be required to be exposed in order to permit utility workers to gain access to the specific utility so as to repair it, splice into it, take a branch from the utility, or whatever other task is required.
However, manholes are typically not very large. A manhole having room for two or three workers may be all that is available, or even smaller, and as such the manhole may have a diameter of not more than 1.5 meters or so. Accordingly, in order to install a protective sleeve somewhere along the length of the duct stretching from that manhole to an adjacent manhole, requires modularity so that the required length of sleeve may be put into placexe2x80x94even though the working space within the manhole might be quite small.
On the other hand, because ducts between adjacent manholes generally run in a straight line, and the distance between the manholes is known; and also because it is possible to fish a tape or line through the duct from one manhole to the adjacent manhole, it is possible to quite accurately position a modular protective sleeve in keeping with the present invention by the use of lanyards which extend from each end of the modular protective sleeve to a respective one of the adjacent manholes, in the manner described hereafter.
It should also be noted that the modular protective sleeve in keeping with the present invention may be assembled without the necessity for any special tools, and without the necessity for hinged structures and the like. The disassembly of modular protective sleeves in keeping with the present invention, when required and appropriate, may be carried out at the site where the utility repair is to take place, because in any event it is necessary to remove the modular protective sleeve away from the utility which it has been protecting after the surrounding concrete casing has been broken away. Of course, it may also be possible to pull the modular protective sleeve back into one or the other of the adjacent manholes which define the length of duct into which the modular protective sleeve has been placed, if necessary or appropriate.
Any modular protective sleeve in keeping with the present invention must be sufficiently strong and rugged to withstand handling in a manhole, and particularly to withstand the shock of a sledge hammer or jackhammer striking it during the course of breaking away the concrete casing which surrounds the utility duct. Accordingly, modular protective sleeves in keeping with the present invention are generally constructed of a strong metal such as case hardened steel, although they may be constructed of aluminum in some circumstances as well.
On the other hand, because a modular protective sleeve in keeping with the present invention does not represent a particularly high capital cost, there are some circumstancesxe2x80x94such as when it is necessary to protect a splice or bypass on a gas line or electrical distribution cablexe2x80x94where once the modular protective sleeve has been put into place it is left in place.
If so, the modular protective sleeve may, itself, be cathodically protected so as to preclude cathodic erosion thereof.
So as to make assembly easy, particularly when a modular protective sleeve in keeping with the present invention is used on a temporary basis, and will be re-used again on another job, and because the modular pieces of the modular protective sleeve tend to look like one another except upon close examination, various distinctive elements may be color coded or are otherwise identifiable due to a specific structural feature, particularly the attachment point for the lanyard which is to be secured at each end of the assembled modular protective sleeve, when in place.
As will be noted hereafter, the modularity of the present invention allows for assembled modular protective sleeves to be put into position at any point along a utility duct, where the assembled modular protective sleeve may comprise as few as three modular elements, having a length equal to the longest of those modular elementsxe2x80x94as described hereafterxe2x80x94or it may comprise a plurality of modular elementsxe2x80x94ranging from 5 up to as many as 11 to 15 elementsxe2x80x94thereby having a length which is an integral multiple of the length of any of the modular elements.
It will also be noted that two of the top elementsxe2x80x94one of which is mounted at each end of an assembled modular sleevexe2x80x94each have one-half the length of the other modular elements which are employed, particularly the first bottom half-shell element, as described hereafter.
Each of the modular elements, on both the top and bottom of the assembled modular protective sleeve, are interlocked one to another so that when they are assembled, a tensile relationship may be established between them. Moreover, because there is a double-acting stop arrangement which is provided at one end of the assembled modular protective sleeve, the use of one lanyard at each end of the assembled modular protective sleeve permits movement of the assembled modular protective sleeve along the utility duct in either direction using the lanyards which are connected, one to the top elements and one to the bottom elements of the assembled modular protective sleeve.
These, and other features and advantages of the modular protective sleeve in keeping with the present invention are described hereafter.
A plastic cable protection sleeve which is fitted around the cable such as a wire rope or hawser, for the cable to pass through when it is towing or mooring a ship is known in Canadian Published Patent Application No. 2,059,776, published Jul. 23, 1992, in the name of Bingham. The structure comprises two half shells which, however, are keyed or hinged together. In any event, as noted, the purpose of this plastic protection sleeve is to protect a cable as it passes over a rail of a ship.
The present invention provides a modular protective sleeve which may be employed in ducts for underground utilities, so as to protect the underground utility during a period of time when the casing around the utility is being broken. The modular protective sleeve comprises a first bottom half-shell which has a first length, first and second ends, and upper edges. The first bottom half-shell has a semi-cylindrical configuration with walls which terminate at the upper edges along the length of the first bottom half-shell.
The modular protective sleeve also comprises first and second top half-shells each of which have a length of one-half the length of the first bottom half-shell. Each of the first and second top half-shells has first and second ends, and lower edges, each of the first and second top half-shells also having a semi-cylindrical configuration with walls which terminate at the lower edges along the length of each of the first and second top half-shells.
The upper edges of the first bottom half-shell each have a stepped configuration, and the lower edges of each of the first and second top half-shells also each have a stepped configuration, but in the opposite sense of the stepping of the first bottom half-shell. Thus, when the first and second top half-shells are placed over the first bottom half-shell, the respective stepped configuration of the upper and lower edges nest into one another so as to form a sleeve having a cylindrical configuration.
The second end of the first top half-shell has a hook-like configuration so as to have a vertically directed hook and an adjacent recess formed therein, in a first vertical direction. The first end of the second top half-shell also has a hook-like configuration, so as to have a vertically directed hook, and an adjacent recess formed therein, in a second vertical direction which is opposite to the first vertical direction. Thus, when the second end of the first top half-shell and the first end of the second top half-shell are placed together, they nest into one another in such a manner that a tensile relationship between them may be established.
Attachment means are provided for a lanyard at each of the second end of the first bottom half-shell and the first end of the first top half-shell.
Stop means are provided at the second end of the second top half-shell in a manner such that the stop means interferes with the end of one of the steps on each of the upper edges of the first bottom half-shell so as to preclude sliding motion of the second top half-shell over the first bottom half-shell beyond a position where the second end of the second top half-shell overlies the second end of the first bottom half-shell.
The above description is of a modular protective sleeve which comprises three elements: two top half-shells, and one bottom half-shell. However, as noted above, the length of the modular protective sleeve in keeping with the present invention may be extended by the addition of further top and bottom half-shells, as now described.
Thus, the modular protective sleeve of the present invention may further comprise at least one second bottom half-shell and at least one third top half-shell, where an equal number of additional bottom half-shells and additional third top half-shells are provided. Each of the at least one second bottom half-shell and each of the at least one third top half-shell have identical lengths. Each has a first end, a second end, and respective upper and lower edges. Moreover, each of the at least one second bottom half-shell and each of the at least one third top half-shell has a semi-cylindrical configuration with walls which terminate at the respective upper and lower edges along the lengths thereof.
The upper edges of each of the at least one second bottom half-shell each have a stepped configuration which is identical to that of the first bottom half-shell.
Also, the lower edges of each of the at least one third top half-shell each have a stepped configuration which is identical to those of the first and second top half-shells.
Thus, each of the first, second, and third top half-shells will nest with the first and second bottom half-shells so as to form an elongated sleeve having a cylindrical configuration.
Each first end of each of the first bottom half-shell and the at least one second bottom half-shell, and each first end of the at least one third top half-shell, has a hook-like configuration so as to have a vertically directed hook and an adjacent recess formed therein in the first vertical direction, as defined above. Also, each second end of each of the at least one second bottom half-shell, and each second end of the at least one third top half-shell, has a hook-like configuration so as to have a vertically directed hook and an adjacent recess formed therein in the second vertical direction, which is opposite to the first vertical direction.
Thus, when any one of the at least one second bottom half-shell is assembled together with the first bottom half-shell, they nest into one another in such a manner that a tensile relationship between them may be established. Further, when any one of the at least one third top half-shell is assembled together with at least the first and second top half-shells, they nest into one another in such a manner that a tensile relationship among them may be established.
In the first embodiment of the present invention, having three elements, the stepped configuration of the upper edges of the first bottom half-shell and the stepped configuration of the lower edges of the first and second top half-shells, may be such that they present an interlocking relationship so as to preclude vertical separation of the first bottom half-shell away from the first and second top half-shells.
Indeed, in any embodiment of the present invention, the stepped configuration of the upper edges of all of the first and second bottom half-shells, and the stepped configuration of the lower edges of all of the first, second, and third top half-shells, may be such that they present an interlocking relationship so as to preclude vertical separation of the first and second bottom half-shells away from the first, second, and third top half-shells.
Also, in any embodiment of the present invention, a first lanyard is attached to the first end of the first top half-shell, and a second lanyard is attached to the second end of the first bottom half-shell, respectively. Thus, the modular protective sleeve of the present invention may be pulled lengthwise in either of a first and second lengthwise direction, by tension being applied to either of the first and second lanyards, respectively.
Typically, the lanyards are calibrated along their length into units of length.
In any embodiment of the present invention, the first bottom half-shell or any second bottom half-shell which may be employed may have a first distinctive colour applied to the inner surface of its semi-cylindrical configuration. Also, each of the first and second top half-shells, and any third top half-shell which may be employed, may have a second distinctive colour applied to the inner surface of each respective semi-cylindrical configuration thereof. The first and second distinctive colours are mutually distinctive one from the other.
Further, there may be a band of a third mutually distinctive colour which is applied to the outer surface of the semi-cylindrical configuration of each of the first bottom half-shell and the second top half-shell, at the respective second end of each.
Any embodiment of the present invention may be formed from a metal such as steel or aluminum.